6 ms·

Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash

89 points by sagitariusrex 8y ago

blakesterz 8y ago
"But just how long the Boeing 777 jet could have stayed airborne would depend on its actual flight path, its altitude and how many of its four engines were operating." Don't the 777s have 2 engines?
- mansr 8y ago
  Yes, they do.
- lstodd 8y ago
  3 including the APU
  - darkpuma 8y ago
    The APU on a 777 provides truly negligible trust; the exaust from the APU is on the left side, not centered, so if it were providing meaningful thrust it would inducing a yaw moment.
    - na85 8y ago
      I think the point is that it draws fuel which reduces the endurance by a small amount
      - craftyguy 8y ago
        I'm pretty sure the generally accepted meaning of an 'engine' in the context of powered flight is 'a thing that provides thrust' and not 'anything that consumes fuel'
      - skookumchuck 8y ago
        The APU is for electric power on the ground, it is not used in flight.
        teeray 8y ago
        ...except in emergency situations. Starting the APU was one of the first things they did during the “Miracle on the Hudson” incident IIRC. It’s conceivable that some in-air emergency happening prior to the loss of communication would have required starting it as a checklist item. EDIT: I just wanted to add that aside from electrical power, it provides bleed air necessary to start the engines, run de-icing (also run A/C packs, operate toilets, etc.) —Hence its usefulness in an emergency situation.
        deleted 8y ago
        [deleted]
        sab0tag3 8y ago
        I think we have agree to rule out that any of the problems affecting this situation resemble an emergency. It can only be flagrant sabotage, or a blunder compounded by savage incompetance. Either they fucked up so bad that they didn't just shoot themselves in the foot, but instead blew their whole leg off. Possible with hypoxia scenarios. Or someone sealed the fate of that flight in cold blood. This version narrative includes the premise of suicide, including single-handed, lone wolf pilot suicide, although other nefarious possibilities fall under this umbrella. The predominant fact of the outcome is that they flew so far off course, and without any distress signals, that their ultimate fate passed into history as a near total enigma which essentially requires strenuous effort or fantastic misfortune.
        darkpuma 8y ago
        In some unusual scenarios the APU may be used during flight. If one of the engine's generators fails the APU might be used to help provide power, and below some altitude the APU in the 777 can provide additional bleed air. In the 777 the left and right hydraulic systems are powered by the left and right engines, but the center hydraulic system has electric and pressurized air driven pumps that I believe can be run off the APU: http://www.flight-mechanic.com/wp-content/uploads/2017/11/12-66.jpg http://www.flight-mechanic.com/wp-content/uploads/2017/11/12... If MH370 lost engine power, maybe it was using the APU to keep the control surfaces active? Who knows. In that sort of situation the 777 would be a glider though.
  - turtlegrids 8y ago
    4 including the Ram Air Turbine (RAT)
    - willyt 8y ago
      The RAT is not an engine and doesn’t deploy unless all other engines have shutdown in flight, and it induces drag because it’s a kind of ‘wind turbine’ that drops into the airstream and generates electrical power (and maybe hydraulic pressure)
      - spdustin 8y ago
        You got that backwards; it “powers” hydraulics, and in some (uncommon) cases, supplies electrical power to other systems.
    - Yetanfou 8y ago
      The RAT is an expensive windmill, not an engine.
- jimueller 8y ago
  Yeah, that jumped out at me too. I don't know how you get that fact wrong.
fromthestart 8y ago
>But the ocean is a noisy place, and Kadri said the underwater sounds might have also been caused by underwater earthquakes... Seismic is rough. Even large earthquake events are localized with large error because of constant noise - seismic event arrivals are hard to pinpoint precisely in time. On top of that, once we have arrival times from a bunch of seismometers(microphones) localization is an inversion problem, dependent on velocity models for a rather heterogeneous earth which further reduces location precision. Even worse, I doubt a crashing jet produces a large magnitude (loud) seismic event, so picking out its arrival in noisy mic data is even harder than it can be for shallow earthquakes. I'd guess a radius on the order of thousands of miles at best, but it's all contingent on how loud the event was and how noisy the mics that picked it up are.
- edmundsauto 8y ago
  For the curious, & because I did the math for myself: 1k mile radius is 3.14 million square miles. The oceans are 140 million square miles.
markoman 8y ago
I'm surprised that no mention was made of the U.S. Navy's network of hydrophones (SOSUS) and whatever took its place in the late 1990s. SOSUS was quite successful at detecting a number of Russian submarines since the 1950s with every new generation thereof. In any event, I can only imagine that there would be U.S. government resources (military and otherwise) that could have provided some surveillance information on what happened to the Malaysian 777 airliner.
- spectramax 8y ago
  I wonder how much information, if any, is withheld by military organizations in various countries. I presume a particular country doesn’t want to give away their latest radar capabilities or what have you by disclosing tracking information whether it’s through satellite systems or through sub-ocean sonar.
  - devonkim 8y ago
    You don't have to disclose capabilities in a press release honestly unless you really, really need to convince people that you're not falsifying the information or trying to mislead people - there is almost no incentive I can think of to mislead people on a general civilian search mission though. A government could simply point some lowly persons to the general area without any explanation of its methods, put almost no official support in funding the search, and it could relieve a great deal of pain and suffering should it lead to findings. The issue may come down to all the scrutiny that could happen were the information lead to the discovery of the plane and (presumably) its passengers. I'm not aware of any government issuing statements like this though in any capacity honestly. It is probably better to assume that our governments, while powerful, are not without their limitations whether it's bureaucracy, technicalities, or simple funding limits.
    - skookumchuck 8y ago
      > it could relieve a great deal of pain and suffering I confess I don't understand this. The families know how their loved ones died, when, and sort of where (in the ocean). How does knowing the precise location help any?
Neil44 8y ago
How frequent are these gravity events during a time period when an airliner isn’t crashing?
ximeng 8y ago
http://mh370.radiantphysics.com/2018/11/17/ocean-infinity-finds-argentine-submarine-after-not-finding-mh370/ http://mh370.radiantphysics.com/2018/11/17/ocean-infinity-fi... “Unfortunately, the acoustics generated by the impact of MH370 on the ocean surface would not propagate along the “deep sound channel” (DSC) the way an underwater acoustic event does, so the impact likely was not detected by CTBTO sensors.” - suggests this is unlikely, although not detailed explanation
- djsumdog 8y ago
  They probably don't have the money or influence to get a search crew out there and are hoping this report will encourage some other treasure hunting group to check it out and confirm/reject their theory.
zyztem 8y ago
Previous analysis of CTBTO hydrophone data (augmented with IMOS, Australian SOSUS clone) back in 2014: https://www.nature.com/news/sound-clue-in-hunt-for-mh370-1.15390 https://www.nature.com/news/sound-clue-in-hunt-for-mh370-1.1...
GrumpyNl 8y ago
With all those satellites in the air, they should able to trace it.

89 points by sagitariusrex 8y ago

"But just how long the Boeing 777 jet could have stayed airborne would depend on its actual flight path, its altitude and how many of its four engines were operating." Don't the 777s have 2 engines?

mansr 8y ago
Yes, they do.
lstodd 8y ago
3 including the APU
- darkpuma 8y ago
  The APU on a 777 provides truly negligible trust; the exaust from the APU is on the left side, not centered, so if it were providing meaningful thrust it would inducing a yaw moment.
  - na85 8y ago
    I think the point is that it draws fuel which reduces the endurance by a small amount
    - craftyguy 8y ago
      I'm pretty sure the generally accepted meaning of an 'engine' in the context of powered flight is 'a thing that provides thrust' and not 'anything that consumes fuel'
    - skookumchuck 8y ago
      The APU is for electric power on the ground, it is not used in flight.
      - teeray 8y ago
        ...except in emergency situations. Starting the APU was one of the first things they did during the “Miracle on the Hudson” incident IIRC. It’s conceivable that some in-air emergency happening prior to the loss of communication would have required starting it as a checklist item. EDIT: I just wanted to add that aside from electrical power, it provides bleed air necessary to start the engines, run de-icing (also run A/C packs, operate toilets, etc.) —Hence its usefulness in an emergency situation.
        deleted 8y ago
        [deleted]
        sab0tag3 8y ago
        I think we have agree to rule out that any of the problems affecting this situation resemble an emergency. It can only be flagrant sabotage, or a blunder compounded by savage incompetance. Either they fucked up so bad that they didn't just shoot themselves in the foot, but instead blew their whole leg off. Possible with hypoxia scenarios. Or someone sealed the fate of that flight in cold blood. This version narrative includes the premise of suicide, including single-handed, lone wolf pilot suicide, although other nefarious possibilities fall under this umbrella. The predominant fact of the outcome is that they flew so far off course, and without any distress signals, that their ultimate fate passed into history as a near total enigma which essentially requires strenuous effort or fantastic misfortune.
      - darkpuma 8y ago
        In some unusual scenarios the APU may be used during flight. If one of the engine's generators fails the APU might be used to help provide power, and below some altitude the APU in the 777 can provide additional bleed air. In the 777 the left and right hydraulic systems are powered by the left and right engines, but the center hydraulic system has electric and pressurized air driven pumps that I believe can be run off the APU: http://www.flight-mechanic.com/wp-content/uploads/2017/11/12-66.jpg http://www.flight-mechanic.com/wp-content/uploads/2017/11/12... If MH370 lost engine power, maybe it was using the APU to keep the control surfaces active? Who knows. In that sort of situation the 777 would be a glider though.
- turtlegrids 8y ago
  4 including the Ram Air Turbine (RAT)
  - willyt 8y ago
    The RAT is not an engine and doesn’t deploy unless all other engines have shutdown in flight, and it induces drag because it’s a kind of ‘wind turbine’ that drops into the airstream and generates electrical power (and maybe hydraulic pressure)
    - spdustin 8y ago
      You got that backwards; it “powers” hydraulics, and in some (uncommon) cases, supplies electrical power to other systems.
  - Yetanfou 8y ago
    The RAT is an expensive windmill, not an engine.
jimueller 8y ago
Yeah, that jumped out at me too. I don't know how you get that fact wrong.

fromthestart 8y ago

>But the ocean is a noisy place, and Kadri said the underwater sounds might have also been caused by underwater earthquakes... Seismic is rough. Even large earthquake events are localized with large error because of constant noise - seismic event arrivals are hard to pinpoint precisely in time. On top of that, once we have arrival times from a bunch of seismometers(microphones) localization is an inversion problem, dependent on velocity models for a rather heterogeneous earth which further reduces location precision. Even worse, I doubt a crashing jet produces a large magnitude (loud) seismic event, so picking out its arrival in noisy mic data is even harder than it can be for shallow earthquakes. I'd guess a radius on the order of thousands of miles at best, but it's all contingent on how loud the event was and how noisy the mics that picked it up are.

edmundsauto 8y ago
For the curious, & because I did the math for myself: 1k mile radius is 3.14 million square miles. The oceans are 140 million square miles.

markoman 8y ago

I'm surprised that no mention was made of the U.S. Navy's network of hydrophones (SOSUS) and whatever took its place in the late 1990s. SOSUS was quite successful at detecting a number of Russian submarines since the 1950s with every new generation thereof. In any event, I can only imagine that there would be U.S. government resources (military and otherwise) that could have provided some surveillance information on what happened to the Malaysian 777 airliner.

spectramax 8y ago
I wonder how much information, if any, is withheld by military organizations in various countries. I presume a particular country doesn’t want to give away their latest radar capabilities or what have you by disclosing tracking information whether it’s through satellite systems or through sub-ocean sonar.
- devonkim 8y ago
  You don't have to disclose capabilities in a press release honestly unless you really, really need to convince people that you're not falsifying the information or trying to mislead people - there is almost no incentive I can think of to mislead people on a general civilian search mission though. A government could simply point some lowly persons to the general area without any explanation of its methods, put almost no official support in funding the search, and it could relieve a great deal of pain and suffering should it lead to findings. The issue may come down to all the scrutiny that could happen were the information lead to the discovery of the plane and (presumably) its passengers. I'm not aware of any government issuing statements like this though in any capacity honestly. It is probably better to assume that our governments, while powerful, are not without their limitations whether it's bureaucracy, technicalities, or simple funding limits.
  - skookumchuck 8y ago
    > it could relieve a great deal of pain and suffering I confess I don't understand this. The families know how their loved ones died, when, and sort of where (in the ocean). How does knowing the precise location help any?

Neil44 8y ago

How frequent are these gravity events during a time period when an airliner isn’t crashing?

ximeng 8y ago

http://mh370.radiantphysics.com/2018/11/17/ocean-infinity-finds-argentine-submarine-after-not-finding-mh370/ http://mh370.radiantphysics.com/2018/11/17/ocean-infinity-fi... “Unfortunately, the acoustics generated by the impact of MH370 on the ocean surface would not propagate along the “deep sound channel” (DSC) the way an underwater acoustic event does, so the impact likely was not detected by CTBTO sensors.” - suggests this is unlikely, although not detailed explanation

djsumdog 8y ago
They probably don't have the money or influence to get a search crew out there and are hoping this report will encourage some other treasure hunting group to check it out and confirm/reject their theory.

zyztem 8y ago

Previous analysis of CTBTO hydrophone data (augmented with IMOS, Australian SOSUS clone) back in 2014: https://www.nature.com/news/sound-clue-in-hunt-for-mh370-1.15390 https://www.nature.com/news/sound-clue-in-hunt-for-mh370-1.1...

GrumpyNl 8y ago

With all those satellites in the air, they should able to trace it.